1. Field:
The invention is in the field of large building construction; or more specifically large concrete type buildings or tanks having configurations or double curvature in nature such as hemispheres or portions of same and various adaptions or variations of hemisphere such as elipsoids, parabolics, cones, cylinders and numerous special shapes, utilizing a slip-form which is moved continuously or intermittently.
2. State of the Art:
Large dome type structures are currently constructed by utilizing a number of methods some of which are: (1) bolting together at the building site segments of prefabricated, pie-shaped structures of steel, wood or other materials, (2) inflating a balloon of fabric or similar material and forming reinforcing wire over it; then spraying a sand, water and cement mixture on it and allowing such mixture to dry before removing the balloon, (3) constructing large forms in pie-shaped segments supported by large beams and structures, then adding reinforcing, after which a layer of concrete is poured and allowed to set before moving the form to a new position where a succeeding pie segment is poured etc. to the completion of the dome, (4) earth is heaped up into a dome shape then reinforcing is added on its surface then sand, water and cement mixture is sprayed on the surface and allowed to set, then the soil is dug out from under the concrete shell.
Other methods and machines have been proposed by the patent literature, see particularly U.S. Pat. Nos. 2,339,892 and 2,607,100 granted to W. E. Urschel, and U.S. Pat. No. 2,877,530 granted to J. B. Winn, Jr.